Adding Up Slider Values for Self-Assessment

You don't need any triggers to set the value of a slider to the value of whatever number the user selects. 

• When you insert a slider, Storyline automatically creates a numeric variable for the slider's value. (It was a good idea to rename your variables to something more meaningful than "Slider[#].") 
• The variable automatically resets when the slider is moved to another position. 
• BTW, you can also move the slider with a trigger that adjusts that variable. 

As for the layers not showing, that's probably because you have the show-layer triggers set to run when the timeline starts for an object called Results Slide 1. 

I don't even see that object on the slide, and I can't explain why it's showing up in the Trigger Wizard. 

In any case, the show-layer triggers should be set to run when the timeline starts on the Results slide. That would show up as "this slide" in the trigger, just like it does for the calculation triggers.